Preparation,microstructures And Properties Of ODS Copper Matrix Composites Reinforced With Graphene

As a new type of two-dimensional layered carbon materials,graphene has excellent mechanical properties and physical properties.Graphene is potential to be widely used in preparing high strength and conductivity copper matrix composites.However,the relevant investigations about graphene reinforced copper matrix composites mainly focus on single-phase graphene reinforced copper matrix composites up to now.The studies on two-phase synergetically reinforced copper matrix composites are rarely found.ODS copper alloys are widely used in the production of electric contact materials,but the process of preparing ODS copper alloys by the traditional internal oxidation method is very complicated,which costs highly in the long production run.Therefore,it is necessary to explore a new process to prepare graphene reinforced ODS copper matrix composites with higher properties and a shorter process.Thus,wet ball milling and hot pressing sintering are applied to prepare G/ODS copper matrix composites.Meanwhile,graphene oxide can be reduced to graphene at a high temperature during the sintering process.The effects of material component,ball milling and hot pressing on microstructures and properties of graphene reinforced ODS copper matrix composites were investigated systematically,which can provide technical reference to the preparation and application of high strength and conductivity copper matrix composites.The influence of materials composition on microstructures,mechanical and physical properties of G/ODS copper matrix composites were studied.The results show that the addition of 0.1 wt.%GO can reduce effectively the number of defects and holes in G/ODS copper matrix composites when the material composition is Cu-0.5Al₂O₃-0.1GO.In addition,the uniform dispersion degree of graphene and superfine alumina is quite good.Both reinforcing phases influence each other in the copper matrix.Their content,dispersion and bonding with the copper matrix co-determine the strenghthening effect.The influence of ball milling process on microstructures,mechanical and physical properties of matrix composites were studied by preparing G/ODS copper matrix composites with different ball milling parameters.The results show that various properties of copper matrix composite powders and copper matrix composites are quite good when the ball milling time is 8 h with the rotation speed of 200 r/min.The ball milling time directly affects the dispersion of GO and superfine alumina.The ball milling speed directly affects the plastic deformation of copper powders and the effective bonding between graphene and copper matrix.The above mentioned parameters can meet the need of actual manufacturing situation with a low cost.The influences of sintering parameters on microstructures and properties of G/ODS copper matrix composites were studied by preparing G/ODS copper matrix composites with different sintering parameters.When sintering temperature is 700?with sintering time of 5min and sintering pressure of 40 MPa,the composites has the compression yield strength of325.33 MPa,tensile strength of 359.46 MPa and hardness of 104.86 HV,which increase by21.12%,28.49%and 32.22%respectively compared with those of ODS copper alloy.The fracture mode is a mixed fracture including ductile fracture and quasi-cleavage fracture.Its tensile ductility is not as ideal as compression ductility.Its electrical conductivity is86.66%IACS.G/ODS copper matrix composites prepared with the above processing parametes have the best comprehensive properties.